Energy Transition Options for Offshore Vessels

Abstract

Abstract The upcoming energy transition - necessitated by the requirement to reduce greenhouse gas emissions - will have a major impact on the offshore market. The future offshore fleet will have to comply with emission regulations and policies that become more stringent over time. Any new build ordered now, must comply to these tightening policies. It is therefore of great importance to make the right decisions on emission reduction technologies and preparing the vessel for future fuel options to keep the vessel compliant over time - as well as gain a competitive edge. The offshore fleet has specific operational requirements that affect the feasibility of zero emission solutions: 1) safety is number one, operational robustness and redundancy are essential, 2) a large endurance is required and trading is global, 3) large load variations may occur and in harsh weather conditions. The Royal IHC cable-lay vessels (CLV) are designed to meet these requirements and are used as a basis in the following analysis. As a side note, an offshore vessel with fixed port of call is mentioned. Many different alternatives are currently presented as zero emission solutions. This paper highlights the different types of fuels and drives systems. The ones that are realistically feasible and ready to order now in an IHC Offshore vessel are explored in this document. 1) Low-sulphur marine gasoil (LSMGO) as base case. 2) Methanol in (dual fuel) combustion engines and fuel cells (with differentiation between LT-PEM and SOFC). 3) Hydrogen as fuel in fuel cells (LT-PEMFC) while taking into account the different storage methods proposed (liquefied, or stored in other medium such as methanol, LNG and ammonia). The researched fuels all have different characteristics with significant implications on the design of the offshore vessel. This paper explains the consequence of the different combinations on the vessel design and operational profile based on implementation in the IHC CLV design. In addition, the paper further explains why these solutions are considered and why other potential solutions have been discarded. Critical to the life cycle performance are the future policies. Several scenarios with varying fuel prices and emission costs are applied in the Life Cycle Performance Assessment (LCPA) tool. The real effect of these choices are thus considered for the entire life cycle of the product. The LCPA calculation results for different fuel types and different policy scenarios provide feedback on capital cost, operational expenses, and voyage expenses. While a CLV is taken as calculation basis, the results provide the audience a LCPA for emission reduction technologies and emission compliance and the effects of that on capital and operational expenses. The insights will be useful for the entire offshore fleet.